Hypodermic syringe.



W. BALL.

HYPODBRMIG SYRINGB.

APPLIOATIQN FILED Nov. ze, 190s.

938,544. muted Nov. 2, 1909.

@VM l Z Y A f m ,MZMZI-f UNITED sTATEs PATENT oEEioE.

WILLIAM BALL, OF ECHUCA, VICTORIA, AUSTRALIA.

HYPODERMIC SYRINGE.

To all whom it may concern:

Be it known that I, VILLIAM BALL, a subject of the King of GreatBritain, residing at Millewa Chambers, High street, Echuca, in the.State of Victoria, Commonwealth of Australia., surgeon dentist, haveinvented an improved Hypodermic Syringe, of which the following is aspecification.

This invention consists of a hypodermic syringe usable for injectingiluid for anesthetic or therapeutic purposes and its essential advantageover other syringes for this purpose is that the piston rod is screwthreaded. and furthermore it may be so arranged that said fluid may bedrawn in and also delivered to the needle by the direct pull or push ofthe hand with the piston in the ordinary manner. while said piston mayalso be at any moment screw fed, whereby the pressure of the Huid `maybe accurately regulated. Moreover by this means the operators hand isrelieved of pressure which formerly often resulted in injury theretowhen forcing fluid into dense tissues or muscular structures, and againby this construction the liability of breakage to the needle is greatlydiminished.

The invention is illustrated by the accompanying drawings whereof g-Figure 1 is a view of the improved syringe, and Figs. 2 and 3 enlargedtransverse sections on line H-II thereof showing the syringe set for thepush and screw feeding of the piston head. Figs. 4, 5, and 6, arecorresponding views to Figs. 1, 2, and 3, showing as modification of theinvention, and Fig. 7 is a rear end view of the piston.

According to this invention the stem 1 of the piston is formed withscrew threads 2 and passes through a collar 3 rotatably seated withinthe. rear end 4 of the metallic casing 5 of the syringe. The casing isformed with a peripheral slot 6 through which a small stud 7 secured tosaid collar projects and by means of which the latter may be partiallyrotated when desired.

The axis 8 of the collar is eccentric to the axis 9 of the piston, andthe bore 10 of said collar has on one side a few interrupted femalethreads 11 cut therein which taper at each side as shown to a point. Therear end 4 of the casing with the threaded collar therein is hereinafterreferred to as a nut.

The threads 2 of the piston stem are adapted normally to pass freelythrough the bore 10 of the collar as shown in Fig. 2 when theSpecification of Letters Patent.

Application filed November 28, 1908.

Patented Nov. 2, 1909.

Serial No. 464,964.

piston is pushed forward in the usual manner, but when the screw feed isrequired the collar is partially rotated within the casing by means ofthe stud 7 into the position shown in Fig. 3. The effect of thismovement is to bring the internal female threads 11 of the collarimmediately into engagementwith the male threads 2 of the piston stem,when by rotating the milled head 12 of said stem, a screw feed of auniform and accurate character will be imparted to the piston.

It will be seen that by turning the stud of the collar in one directionor the other by means of the operator-s finger that the threads of thepiston stem and collar may f be immediately disengaged or engaged, thusconverting the syringe into a push or screw feed at will.

lf desired the rear face of the milled head 12 of the stem may becalibrated as shown in Fig. 7 so as to enable the operator to regulatethe injection carefully when the usual graduations marked on the sidesof the glass cylinder 13 of the syringe cannot be conveniently seen.

In order to dispense with the necessity of bringing into use one of theoperators fingers to change the piston from the push to the screw feedor vice versa. the modication shown in Figs. 4, 5, and 6, may beadopted. In this ease the collar stud and slot in the casing areunnecessary and said casing is formed with a few internal interruptedthreads 14 in its near end or nut 4, while the threads 15 of the pistonstem are also interrupted and a longitudinal recess 16 is formed in thestem between the ends of the interrupted threads thereof.

Zhen the threads are disengaged, i. e. when the internal teeth of thechamber are in t-herecess 16 of the stem as in Fig. 5 the piston is freeto move longitudinally by means of a push stroke, but by partiallyrotating the piston or its casing without releasing the hold of theinstrument by either hand, the teeth on the stem of the piston arebrought into engagement with those of the casing as in Fig. 6 and ascrew feed is obtained.

The piston head 17 is loosely attached to the stem 1 so that when thelatter is rotated the head simply moves directly forward against thecontents of the syringe without any unnecessary rotation.

Having now particularly described and ascertained the nature of my saidinvention and in What manner the same is to be per formed, I declarethat what I Claim is l. In a hypodermic syringe, a Casing provided atthe rear end with internal interrupted threads, a piston provided With athreaded stein adapted to'engage with said threads and means to put thethreads of said piston stein and said casing in or out of engagementforthe purpose specified.

2. In a hypodermic syringe, a casing, a piston provided With a threadedstem, a partially rotatable collar Within said easing mountedeeeentrically to said stem Which passes therethrough, internalinterrupted threads in said collar and means to partially rotate saidcollar as and for the purpose speeied.

3. In a hypodermic syringe, a casing, a piston provided With a threadedstem, a par.- tially rotatable collar Within said easing mountedeecentrically to said stem, which passes therethrough, a central bore insaid collar yformed in one side With internal threads tapering at eachend, a peripheral 'slot in said casing andV a stud on said collarprojecting through said slot as and for the purpose speeiiie et. In ahypodermie syringe, a cylinder, a piston and a piston rod, the cylinder'provided With a threaded nut, the rod threaded to cooperate With thenut, one of said threads being interrupted. l

5. In a hypodermic syringe, a cylinder, a piston and a piston rod, thecylinder yprovided With a threaded nut, the rod threaded to cooperateWith the nut, one of said threads being interrupted, vand means forthrowing the threads of the rod and nut into and out of engagement.

In testimony whereof I have hereunto set my hand in presence of tivosubscribing Witnesses.

WILLIAM BALL.

IVitnesses SELINA JANE BELL, ALBERT VICTOR ELLIS.

